The present invention relates to a semiconductor device and its manufacturing techniques. Specifically, for example, the present invention relates to techniques that are effective when applied to a semiconductor device including a first power transistor and a second power transistor that are reversely coupled in series to each other in the same semiconductor chip, as well as applied to its manufacturing techniques.
Japanese Unexamined Patent Application Publication No. 2011-35322 (Patent Document 1) describes a technique to form a back electrode so that it is embedded within a concave portion in a back surface of a semiconductor substrate and covers at least part of the area except the concave portion in the back surface of the semiconductor substrate.
Japanese Unexamined Patent Application Publication No. 2006-156658 (Patent Document 2) describes a technique to form a back electrode in a bottom surface of a groove that is provided in a back surface of an SiC substrate, and to form a conductor so as to fill the groove.